{"id":"UBUNTU-CVE-2026-49114","details":"In ONNX before 1.21.0, the 'save_external_data' function builds the external-data file path from the model's external_data location field and opens it for writing without 'O_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim's write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.","modified":"2026-09-02T19:36:24.243564025Z","published":"2026-08-21T16:17:00Z","upstream":["CVE-2026-49114"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-49114"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-49114"},{"type":"REPORT","url":"https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6"}],"affected":[{"package":{"name":"onnx","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/onnx?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.0+dfsg-3build1","1.7.0+dfsg-3build2","1.7.0+dfsg-3ubuntu1","1.7.0+dfsg-3ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"libonnx-testdata","binary_version":"1.7.0+dfsg-3ubuntu2"},{"binary_name":"libonnx1","binary_version":"1.7.0+dfsg-3ubuntu2"},{"binary_version":"1.7.0+dfsg-3ubuntu2","binary_name":"libonnxifi"},{"binary_version":"1.7.0+dfsg-3ubuntu2","binary_name":"python3-onnx"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49114.json"}},{"package":{"name":"onnx","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/onnx?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.13.1-3","1.13.1-3build1","1.14.1-2","1.14.1-2.1","1.14.1-2.1build1","1.14.1-2.1build2","1.14.1-2.1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.14.1-2.1ubuntu0.1~esm1","binary_name":"libonnx-testdata"},{"binary_name":"libonnx1t64","binary_version":"1.14.1-2.1ubuntu0.1~esm1"},{"binary_version":"1.14.1-2.1ubuntu0.1~esm1","binary_name":"python3-onnx"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49114.json"}},{"package":{"name":"onnx","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/onnx?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.17.0-3build1","1.20.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libonnx-testdata","binary_version":"1.20.0-1"},{"binary_name":"libonnx1t64","binary_version":"1.20.0-1"},{"binary_version":"1.20.0-1","binary_name":"python3-onnx"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49114.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}